Abstract
A 66-year-old man was admitted with anasarca and congestive cardiac failure. He was started on intravenous diuretics and fluid restriction and lost nearly 35 kg of fluids in 13 days. He then developed hyperthermia and delirium. An extensive workup was inconclusive. Analysis of his inpatient fluid balance chart revealed the chance association of massive fluid loss and hyperthermia. Rapid diuresis-induced hyperthermia and volume contraction were considered, and his fluid balance was adjusted. Within 2 days, his temperature normalized and he regained consciousness. Hyperthermia and its causative mechanism are discussed in this article.